Devices and systems for cooling a magnetic device by convective fluid flow are disclosed and, more particularly, devices, systems, and methods using a strip-laminated, ribbon-type conductor having an insulating portion that is structured and arranged, spirally and coaxially, with the ribbon-type conductor so that the insulating portion is disposed between adjacent conductor sections.
Design of magnetic devices, e.g., electromagnet coils for magnetic bearings, has included laminated coils and/or laminated cores. However, resistive losses and core losses resulting from eddy currents and/or hysteresis, and electrical conduction losses produce relatively-high, internal heat, requiring cooling to maintain material temperatures within acceptable operating limits.
Potted structures such as coils made with round conductors and insulated and/or encapsulated in an epoxy or ceramic, offer desirable properties such as protection from oxidation, insulation resistance in a high-temperature environment, i.e., greater than 200 degrees Centigrade (° C.), and improved dielectric strength in a high-temperature environment. However, potted structures, typically, transfer heat by conduction, which makes heat removal less than ideal and have low packing factor.
In one electromagnet coil application, mica insulation was disposed between wound layers of nickel-plated copper strips. However, over time, at operating temperatures in excess of 500° C., nickel diffusion degraded the conductivity of the copper and the effectiveness of heat transfer was limited. Accordingly, it would be desirable to provide a system and a device for cooling magnetic devices, e.g., electromagnet coils.
It also would be desirable to provide a system and a device for cooling magnetic devices for an electromagnet coil having a high packing factor, e.g., 75 to 80 percent.
It would further be desirable to provide a system and a device for cooling magnetic devices that reduce short- and long-term degradation of conductivity at elevated temperatures.
It would also be desirable to provide a system and a device for cooling magnetic bearing coils, inductor coils, inductor cores, shaker field cores, and the like.